Given the task definition, example input & output, solve the new input case.
In this task, you're given an article and an answer. Your task is to generate the question for the answer based on the given article.
Example: Article: There are a lot of public libraries in Britain. These libraries have more than one hundred and fifteen million books, not including those libraries of public schools. Public libraries not only lend books, music records but also help children, patients in hospitals and others to get special play readings, film shows and so on. The first public libraries were founded in about the year 1850. Today's public libraries usually have a reading-room, a lending room and a reference room. The greatest and most famous library in Britain is that of the British Library in London. It was founded in 1973 and has over 10, 000, 000 books. It has nearly every magazine, newspaper and book published in Britain and other parts across the world. 
 Answer: 10,000,000 or less.
Output: How many books are there in the British Library?
In the Article, 10,000,000 is mentioned for the number of books available in the British Library, so this is a good question.

New input case for you: Article: Farmers can produce more by planting several different crops in the same field.But their success depends on which crops they plant together and how they mix   them in the filed.In the past, the only way the farmers could learn which crops grow best together is to plant them and wait for the results.Now, however, a computer can give them answers.A new computer program written by Dr John Vanderwell of Michigan University can tell a farmer which plants grow well together and which do not.It can tell him how to plant the different crops; if he should plant each in a separate row, or mix the crops in the same row.It can tell the farmer how changes in planting each of the crops will affect the production of all of them.And it can tell him which plants can help reduce losses   from diseases. 
 Answer: Computer helps produce more crops.
Output:
Which of the following best gives the main idea of the passage?